The purpose of this project is 1) to objectively evaluate the efficacy and clinical toxicity of drugs given to outpatients to alleviate apprehension associated with dental procedures, 2) to study the physiological, psychological and biochemical responses to the stress of dental therapy, and 3) to evaluate the role of exogenous epinephrine administered with local anesthetic on cardiovascular performance. Special attention has been given to the non-invasive measurement of cardiac output and stroke volume by thoracic impedance cardiography. A recent study employing this methodology indicates that exogenous epinephrine administered with local anesthesia results in an increase in circulating epinephrine levels and that there is a concommitant increase in cardiac output. A parallel investigation indicated that the elevated epinephrine levels and elevated cardiac output are not attenuated by diazepam premedication. Diazepam premedication does appear to suppress the elevation in circulating norepinephrine levels seen in non-sedated patients. These findings suggest that exogenously administered epinephrine results in an increase in circulating levels and a resultant increase in cardiac output.